1. Field of the Invention
The present invention relates to a method of manufacturing a liquid crystal display apparatus which carry out display by reflecting externally incident light.
2. Description of the Related Art
In recent years, application of liquid crystal display apparatuses to word processors, laptop personal computers, pocket televisions and the like has rapidly been progressing. Of the liquid crystal display apparatuses, reflective-type liquid crystal display apparatuses which carry out display by reflecting externally incident light are attracting attention because the reflective-type liquid crystal display apparatuses are low in power consumption, thin and capable of being reduced in weight since no backlight is necessary.
However, in the conventional reflective-type liquid crystal display apparatuses, the brightness and the contrast of the display are dependent on the use environment such as ambient brightness or the use condition. Therefore, at present, high expectations are placed on the realization of a reflective-type liquid crystal display apparatus that has excellent reflection characteristics, can easily be manufactured with excellent reproducibility and is high in display quality.
Japanese Unexamined Patent Publication JP-A 6-75238 (1994) discloses a technology to form random and high-density asperities on a reflecting electrode in order to improve the display quality of the reflective-type liquid crystal display apparatus.
According to this, a resin layer for adding fine asperities to a reflecting electrode comprises a first photosensitive resin layer patterned with random asperities and a second photosensitive resin layer for making the asperities smoother, and in a mask for patterning the first photosensitive resin layer, circular light intercepting portions are randomly disposed and the total area of the light intercepting portions is not less than 40% of the area of the reflecting plate.
By increasing the randomness as described above, the interference due to the repetitive pattern is prevented and the reflecting light is prevented from being colored, and by increasing the density of the asperities, the area of the flat part is reduced to thereby reduce the regular reflection component.
Moreover, Japanese Unexamined Patent Publication JP-A 9-90426 (1997) discloses a technology to simultaneously expose an asperity forming pattern and contact holes using only one layer of a photosensitive resin in order to reduce the process of manufacturing a reflective-type liquid crystal display apparatus.
A method of manufacturing a reflective-type liquid crystal display apparatus described in this patent publication will briefly be described with reference to the drawings. In this regard, FIG. 22 illustrates a mask used in this reference (JP 9-90426).
In the reflective-type liquid crystal display apparatus described in the above-mentioned patent publication, the following are provided: an aluminum pixel electrode disposed on the reflecting substrate; a transparent electrode opposed thereto; a color filter substrate supporting the transparent electrode; liquid crystal sandwiched therebetween; and a polarizing plate 116 disposed above the phase difference plate 115.
A method of manufacturing the reflecting substrate of the reflective-type liquid crystal display apparatus described in the above-mentioned patent publication will be described.
First, a photosensitive resin is applied to the substrate.
Then, exposure is carried out using the photomask shown in FIG. 22 having a large light-blocking contact hole portion and in addition thereto, a plurality of smaller light blocking portions at asperity forming portions
Then, by development a resin configuration with respect to the mask pattern is formed.
Then, a thin film is formed as the reflecting electrode over the asperities defined in the resin.